Relief-valve for compressors



(No Model.) I 6 H. 0. REINHARDT;

RELIEF VALVE FOR GOMPRESSORS.

No. 367,236. Patented July 26, 1887.

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L\\\\\\\\\\\ I r UNITED STATES PATENT OFFICE.

' HERMANN O. REINHARDT, OF CHIHUAHUA, MEXICO.

'RELlEF-VALVE FOR COMPRESSORS.

$PECIPICATIONforming part of Letters Patent No; 367,236, dated July 26, 1887.

Application filed January 13, 1867. Serial No. 224,198. (No model.)

pump driven by a steamengine and located.

at a considerable distance from the drills. In such cases the compressor forces air into a tank, called an accumulator, and the several machines to be operated derive their supply directly from the accumulator. As machines go into and out of action, the drafts upon the accumulator will vary and the pressure therein will correspondingly vary, while the supply from the compressor running at uniform speed will be constant. It is therefore necessary to provide a regulator which will prevent an over pressure in the accumulator which might endanger the apparatus. At the same time the motive engine is frequently employed to propel other machinery than the compressor, and therefore the required regulation cannot be attained by Varying the speed of the engine. It is known, too, that economy is best secured by preserving a uniform speed of the moving parts and by regulating the expenditure of steam in accordance with the work to be performed; It is desirable, therefore, to maintain a uniform speed in the engine and a uniform pressure in the'accumulator, and to cut off back pressure or resistance while air is not being forced into the accumulator.

The object of my invention is to open a relief-valve and enable the compressor to run without resistance from back-pressure during the period when the pressure in the accumulator remainsat this predetermined maximum and automatically to close again to permit the compressor to force into said accumulator the moment the pressure therein drops to or below said maximum. To accomplish this result two things are indispensable: first, a balanced relief -valve loaded to the desired maximum, butnot influenced by fluid-pressure in the conduit pipe or compresser, but connected with the accumulator to be controlled, opened by pressure therein when the maximum pressure has been attained; and, second, a check-valve between said relief-valve and the accumulator, to prevent escape of fluid from the accumulator when the relief-valve opens. The relief-valve must be opened by back-pressure in the accumulator, because it is therein that the pressure requires to be regulated. It must be balanced, so that it will close again immediately the pressure in said accumulator drops below the maximum, which it would not do if subjected to fluid-pressure in the pipe. The check-valve is necessary to prevent escape from the accumulator through the relief-valve and to permit the compressor to run without back-pressure resistance while the relief-valve is open.

So far as I am aware no apparatus has heretofore combined a balanced relief-valve controlledby back-pressure in the accumulator and loaded to resist a certain predetermined maximum pressure therein, and a check-valve betweensaidrelief-valve andsaid accumulator.

--Having now set forth the object and essential elements of my invention, I will particularly describe the mechanism as I have preferred to make it, without intending to limit myself to the particular structural details shown, as they may be greatly varied'without changing the essential conditions, as above named.

Figure 1 is an elevation, partly in section, showing my invention. Fig. 2 is a vertical longitudinal section enlarged from Fig. 1. Fig. 3 is a horizontal central section through the relief-valve on line so a Fig. 4 is a diagram illustrative of the operation.

A is the conduit pipe or main leading from the compressor U, of which a is the pistonrod to the accumulator V, both of which may be of any kind suitable for the duty required.

W is an ordinary puppet check-valve to prevent the return of air from the accumulator toward the compressor.

F is the relief -valve interposed in or connected with the main A, so that when opened it will enable the compressed fluid to escape directly tothe open air, and, as the contents of the accumulator are at times isolated by the puppet-valve \V and cannot return to the relief-valve, the fluid from the compressor will flow out freely and without resistance into the surrounding atmosphere. The valve F is loaded in correspondence with the maximum accumulator-pressure, and is constructed with two seats, or otherwise balanced against the fluid-pressure in the main A, and is connected with a piston or other motor subjected to motive pressure of the fluid in the accumulator, said pressure being counterbalanced by a weight up to the predetermined maximum, so that when the predetermined maximum pressure in the accumulator has been attained said weight will be overcome and the relief-valve will be opened, and being balanced as to the pressure in the main it will close again immediately when the accumulator-pressure falls below said maximum. This it would not do if said valve were held to its seat by fluidpressure, because, referring to Fig. 4, if said fluid-pressure tended to hold said valve to its seat and the same fluid-pressure, acting upon the piston F, tended to lift the valve from its seat, it is plain they would balance each other, area for area. Therefore it would be necessary to make said piston exceed the valve-area and to counterbalance the excess with a weight equivalent to the maximum pressure. The said excess would then constitute the operative part of the piston in lifting the valve; but as soon as the relief-valve leaves its seat the fluid-pressure upon it is relieved and it ceases to balance a portion of the piston. Therefore the reliefvalve will be kept open until the pressure in the accumulator has fallen sufficiently below the maximum to permit the piston-weight to overcome the entire piston-pressure. Forinstance, suppose the relief-valve to have an area of four square inches, and the piston to have an area of eight square inches, and the maximum pressure to be one hundred pounds per inch, then the relief-valve would be subjected to a pressure of four hundred pounds, and this would balance one-half the piston pressure of eight hu11 dred pounds. The other half of the pistonpressure will then be counterbalanced by an equivalent weight; but as soon as the accumulator-pressure exceeds one hundred pounds per inch the weight will be overcome and reliefvalve opened. Upon leaving its seat the fluidpressure upon it is immediately relieved and no longer balances a part of the piston-pressure, and the piston being still subjected to the pressure of eight hundred pounds will be only halfconuterbalanced by the weight offourhundred pounds. Under these conditions it is evident this weight cannot close the valve again until the pressure in the accumulator has fallen to fifty pounds; but if the reliefvalve is self-balanced in some one of the well-known ways the effective piston-area and the couuterbalancing-wcight will never change their relative efficiency, and the valve will be opened or closed within a fraction above or below the predetermined maximum pressure.

For the sake of compactness and cheapness we have preferred to provide the main A with a double valve-seat, D and E, the former external as to the main A and the latter concentric with and a little smaller than the seat D; but at the extremity of a cylindrical shell, O,within the main the valve F is hollow, and is fashioned to close on both of these seats, and when opened fluid escapes by way of both seats D and E. The opening within the seat D is just enough larger than the seat E to permit the inner part of valve F to pass through it to the seat E, as is commouin many balanced valves. The valve F being hollow, the fluid escaping beneath it finds vent by afterward passing through said valve. It is necessary that the valve F shall be provided with a guide and with a motor controlled in one direction by the fluid under pressure in the accumulator. These we conveniently combine in the sleeve F, attached to the valve F, and the stud 13, attached to the main A and located centrally and concentric as to the shell 0. The sleeve F is connected with the valve F by radial webs F and at its top there is a socket-seat, F, for the end of pressure-stud M, which transmits to said valve the counterbalancing-pressure from the lever L and weight N. The exterior surface of the stud B is turned truly to act as a guide, and the sleeve F is truly bored to fit said stud, and the valve F is thereby guided in its movements. The stud. B may also act as a stationary piston, and the sleeve F may act as a motive cylinder to move the valve when fluid under pressure is admitted between them. I therefore perforate said stud, as at O, and by means of a pipe, I, connect the same with the accumlator or with the main A on the accumulator side of the checkvalve W, so that the cylinder-space Z, between the head of the stud B and the sleeve F, may be filled with fluid having the same pressure as the fluid in the accumulator, and to prevent escape of the same packing R is employed and conveniently retained in place by a cap, S, fastened to the top of the stud B by means of a hollow screw, T.

The lever L is pivoted to the stud G, and is kept in place laterally by passing through the slotted standard H. Its motion may be limited by the stop-screw K.

Having described my invention, I claim- The main A, provided with the interior shell, 0, having the seat D at its extremity, with the exterior seat, E, and with the cylindrical perforated stud B concentric with the shell, and having its perforations con- IIO nected with a supply of fluid under pressure, by fluid between said stud and sleeve when combined with the balanced relief-valve F, the pressure therein becomes suflicient to lift adapted at its ends to close onto the seats D said weight, substantially as set forth.

and E, respectively, saidvalvebeing provided HERMANN O. REINHARDT. with an axial sleeve, F, fitte.d to slide over Witnesses:

said stud, and a counterbalanoing-weight, W. O. ROLLINS,

whereby said valve will be raised and opened FELIsE BAZET. 

